This invention relates to methods and apparatus for mounting and inflating tubeless vehicle tires on wheel rims. More specifically, it relates to such methods in which a minimum of apparatus is supplemented with the use of a special plastic material to form an airtight seal between the tire and wheel rim.
The difficulty of solving the problem of safely mounting and inflating vehicle tires on wheel rims is indicated by the considerable variety of apparatus that has been invented and that is currently on the market for this purpose. Most of these devices involve elaborate and dangerous hardware.
Tubeless, pneumatic tires are ordinarily mounted on wheel rims in a horizontal position, the side walls of the tire being placed between the wheel rim flanges. In this position, the lower side wall bead of the tire is in contact with the adjacent wheel rim flange and forms an adequate, gastight seal therewith. However, causing the upper side wall bead to form a seal with its adjacent wheel rim flange long enough to inflate the tire has been a considerable problem.
Certain prior art devices for doing this have included bands or belts applied to the tread of the tire that, when tightened, constrict the tire radially to force the upper side wall bead of the tire into sealing contact with its adjacent wheel rim flange until the tire is inflated. Such devices are under a great deal of tension and have been known to break with the release of considerable force, so that they are dangerous to use. Also, they tend to be unsatisfactory when used with recent types of tires, such as radial or belted tires that contain bands or belts of substantially incompressible materials under their treads, such as steel wire or fiber glass.
Some prior art devices include a dome enclosing an annular air chamber that is pressed downwardly to form a seal against the tire side wall to enclose the side and wheel rim during inflation of the tire. Others include an annular band that is used in a similar manner. These devices usually require the use of apparatus for holding the annular sealing means axially against the tire or against both tire and rim. Experience has shown that it is difficult to maintain a gastight seal with both tire and rim as air is introduced under pressure to inflate the tire.
U.S. Pat. Nos. 3,596,698; 3,658,109; 3,654,980; and 3,081,816 teach the use of flexible annuli that are inserted into the gap between the upper side wall bead and its adjacent wheel rim flange. These devices, also, have proved to be unsatisfactory for several reasons: some are flexible but nonelastic, so that an annulus of a different size must be used for each size of tire and wheel rim; those that are elastic are difficult to stretch over the wheel rim flange; and, in general, they tend not to provide the intended gastight seal between the surfaces of the tire and wheel rim.
More recent devices have attempted to solve this problem by providing an annular manifold having a ring of tiny orifices through which air under very high pressure is suddenly forced into the gap between the upper tire side wall and the wheel rim flange, as the inflating air is also introduced. This device is also limited to use with tires and wheels of a special range of sizes. Also, air jets are forced through the orifices under such high pressure that they present a constant risk of injury to the operator.